Halogen containing derivatives of dicarboxylic acids



v a hydrocarbon radical.

- "of alpha bromo beta-trichloromethyl succinic Patented Mar. 22, 1949 GDERIVATIVES DICARBOXYLIC ACIDS HALOGEN COQHNIN Morris S.Kharasch,limeigif llla assignor to United States Rubber Company, NewYork, N. Y., a corpujtion of New Jersey No Drawing.

pplication October 25, 1947, erial n. 782,219

4 Claims. -(o1.act-485) This invention relates to the synthesis or'a newclass of chemicals consisting of the 1,1,1-

trichloro-5-bromo-2;3-dicarbalkoxy alkanesand their dehydrobrominatedderivatives which are 1,1,1-trichloro-2,3-dicarbalkoxy-4-alkenes. Thesenew compounds have the type formulae A a-o-c- H-CEb-(BB-Br l 7 and I HROG-(E-CCI;

respectively, wherein R is a saturated aliphatic hydrocarbon radical, Ais either hydrogen or a hydrocarbon radical, and B is either hydrogen orThese new chemicals which are useful as intermediates in organicsynthesis in the preparation of dyes, pharmaceuticals, plasticizers,insecticides and resins are produced by causing dialkyl esters acid toreact with an ethylenically unsaturated organic compound by maintainingthe dialkyl alpha bromo beta trichloromethyl succinate and theunsaturated compound in contact with a peroxidic catalyst until the1,1,1-trichloro-5- bromo-2,3-dicarbalkoxy alkane is formed. This productreadily loses hydrogen bromide to form a1,1,1-trichloro-2,3-dicarbalkoxy-4-alkene.

The dialkyl esters of alpha-bromo-beta-trichloromethyl succinic acidwhich are used in accordance with the present invention to produce thenovel and useful 1,1,1-trich1oro 5-bromo-2,3- dicarbalkoxy alkanes andthe 1,1,1-trichloro-2,3- dicarbalkoxy-i-alkenes may be produced by themethods disclosed and claimed in my copending application 782,220, filedOct. 25, 1947.

These dialkyl esters may be produced by the free radical initiatedreaction between'trichlorobromomethane and either a dialkyl fumarate ora dialkyl maleate such as for example by the 60' photochemical reactionbetween trichlorobromomethane and dimethyl fumarate.

Among the terminally unsaturated organic compounds which are suitable inthe practice of my invention are:

1. Octane-1 2. Isobutylene 3. Methallyl chloride 4. Undecylenic acidesters (preferably the methyl esters) 5. Butene-l 6. 2-ethylbutene-1 '7.Allyl chloride (Oleflns containing an aromatic group attached to acarbon of the ethylenic structure, 1. e.. styrene, are excluded, sincethey will polymerize.)

Also, cyclic olefins, such as cyclohexene are excluded, since noaddition in the manner indicated takes place.

as sodium persulfate and the like.

The following examples are illustrative of my invention:

- EXAMPLE 1 Preparation of 1,1,1 -trichloro-3bromo-2,3-dicarbmethozcypropane (dimethylalpha-bromobeta-trrichloromethyl succinate) perature of the reactants ismaintained at -60 C. by the illuminating coil. The undissolved,crystalline fumarate ester completely disappears in fifteen hours.Unreacted bromotrichloromethane (155 g.) is' recovered by distillationat 1'01104 C. at atmospheric pressure. Further distillation of theviscous residue (75.5 g.) at .1 mm. yields 2 g. of unchanged dimethylfumarate at 90 C. a-colorless oil (fraction 1) (57 g.) at -108 Clwhichpartly solidifies and a viscous, light yellow oil (fraction II) (11.9g.) at 185 0. A black, viscous residue (4.1 g.) remains.

Exmu 2 Peroxide-induced addition of 1,1,1-t1'ichloro 3-bromo-2,3-dicarbmethozy propane to octene-I The 1:1 adduct oftrichlorobromomethane and dimethyl fumarate (fraction I of Example 1)(11.42 g., 0.033 mole) and acetyl peroxide (0.2 g.) are dissolved inoctane-1 (11.2 8., 0.1 mole) at '75-80 C. with stirring over a period orthree hours.

The stirring and temperature are maintained for one hour after additionis complete. AIter cooling, the unreacted octene (18.0 g.) is distilledat reduced pressure. Further distillation of the residue gives aslightly viscous, colorless liquid (11.3 g.) distilling at 160170 C. at.1 mm. and

an orange-black residue (1.7 g.). Hydrogen bromide is given 011 during.the distillation and collected in a liquid nitrogen trap. The additionproduct (10.1 g'.) is treated with the calculated amount of sodiummethylate in methanol to remove all bromine in the molecule. The product(7.1 E.) distills at 165-170 C. at .2 mm. and is only slightly viscous.The halogen analysis and molecularweight are consistent with1,1,l-trichloro-2,3-d.icarbmethoxyundecene-4.

Anal. calcd. for C15H2aO4Cl:-Cl, 28.6. Found: Cl, 28.0.

Molecular wgt. calcd. for CuHaaOiCla-373.5. Found: 370.5.

Identification of addition product of bromotrichloromethane-dimethyljumarate 1:1 addition product to octene-i (1.1,1-trichloro-5-bromo-2,3-dicarbmethozyundecane) A 4.9 g. sample of the unsaturated additionproduct is dissolved in ethyl acetate and treated with ozone at -75 C.The ethyl acetate was evaporated in vacuo and the oily residue istreated with water at C. for twenty-four hours and at 60 C. for twohours. It is then steam distilled and the distillate is extracted withether. The oily extract (0.5 g.), similar in odor to heptaldehyde, givesa precipitate with 2,4-dinitrophenylhydrazine reagent. The precipitateis recrystallized from ethanol. It melts at 101-103 C. and does notdepress the melting point of an authentic sample of the2,4-dinitrophenylhydrazone 0t heptaldehyde. No evidence of the presenceof oxalic acid is found in another portion of the steam distillate afteroxidizing with hydrogen peroxide and refluxing with dilute hydrochloricacid.

The water insoluble residue, non-volatile in steam, is separated, driedand fractionated giving 1.0 g. of oil distilling at 145-155" C. at .1mm. as well as 2.4 g. of oil distilling at l65-170 C. which is probablyunchanged starting material. The lower boiling fraction has a halogenanalysis approximating 1,1,l-trichloro-2,3-carbmethoxybutyraldehyde.

Anal. calcd. for CoHroOsCla-Cl, 34.6. Found: Cl, 33.0.

If one substitutes for the octene-l in Example 2 any oleflnic compoundfrom the group consisting of isobutylene, methallyl chloride, alkylundecylenic acid esters, butene-L2-ethyl butene-l and ally] chloride thereaction illustrated by Example where A, B and R are as previouslydefined.

The reactions involved in the present invention may be summarized by thefollowingseries of equations:

1. R'-O00-CR' a'-+ Copi g-R O coon coon a R'- nrcn-tn-cci. R'Brcn-dncc1.

I II 3. A\ 0001: A\ 000R c=cm ':n-cncc1. c-cHrcnn-cci. B R00 B R00 11 m4. A\ coon coon o-crr.cn-dn-cc1.+ n'rcn-tn-coi. B R00 1100 m 1 coca coonUHrCH-(5H0Oh+ err-direc n 1' R00 R00 W n a.

A coca c-cm-cn- 11-001,

a r aoo C=CH--CH- H0Ol Hill a coon c=cn-crrn-cc -zo. n aoo a coon c=oo=crr-cn-tn-cc1.+zo, B 1:00

VI VII Equation 1 illustrates the formation of free radicals by thedecomposition of a dlacyl peroxide and one of these free radicals canreact as in Equation 2 with a molecule oi alpha bromo betatrichloromethyl dialkyl succinate (I) to remove a bromine atom formingan organic bromide and a free dialkyl beta trichloromethyl succinateradical II. Equation 3 illustrates the addition of radical H to a,terminally unsaturated oleflnic compound to form the new tree radicalIII which as shown in Equation 4 can remove a bromine atom from amolecule of a dialkvl alpha bromo beta trichloromethyl succinatc to forma molecule of the 1,1,l-trichloro-5-bromo-2,3-dicarbalkoxy alkanederivative IV and generate another free radical II which byparticipating in reaction (3) can carry on the chain. Equation 5illustrates the dehydrobromination of IV to form the alkene derivativeV. Equation 6 illustrates the reaction whereby the structure of V isestablished. The

1 methoiwundecene- -l.

6 pane, a terminally unsaturated oleflnic compound and a peroxidiccatalyst until a 1,1,l-trichloro-5- bromo-2,3-dicarbalkoxy alkanederivative is formed treating the 1,1,1-trichloro-5-bromo-2,8-dicarbalkoxy alkane derivative with an alkaline dehydrobrominating agentand isolating the 1,1,1- trichloro-2,3-dicarbalkoxy-4 alkene.

3. The process of producing 1,1,i-trichloro-2,3- dicarbmethoxyimdecene-4which comprises heating a reaction mixture containing1,1,1-trichlor0-3-bromo-2,3-dicarbmethoxy propane, octene-l and 'a diacyl peroxide until1,1,1-trichloro-5- bromo-2,3-dicarbmethoxyundecane is formed, treatingthe 1,1,1-trichloro-5-bromo-2,3-dicarbmethoxyundecane with an alkalinedehydobrominating agent and isolating the 1,l,1-trichloro-2,3-dicarbmethoxyundecene-4.

4. The chemical 1,1,1',-trich1oro-2,3-dicarb- MORRIS S, KHARASCH.

No references cited.

